2 1/4 c. sifted cake flour
1 1/2 c. sugar
3 tsp. baking powder
1 tsp. salt
1/2 c. salad oil
7 egg yolks
3/4 c. cold water
1 tsp. vanilla
7 egg whites
1/2 tsp. cream of tartar
1/4 c. boiling water
2 tbsp. sugar
2 (1 oz.) squares unsweetened chocolate, melted

Sift together first 4 ingredients. Make well in center of dry ingredients and add in order next 4 ingredients. Beat until satin smooth. In large bowl, beat egg whites with cream of tartar until very stiff peaks form. Pour egg yolk mixture in thin stream over entire surface of egg whites, gently folding to blend. Remove 1/3 portion of batter. Spoon half the light batter into ungreased 10 inch tube pan; top with half the chocolate batter. Repeat layers. With narrow spatula, swirl gently through batters to marble. Bake in slow oven (325 degrees) about 55 minutes or until cake tests done. Invert cake in pan; cool. Frost with chocolate frosting.

CHOCOLATE FROSTING:

6 tbsp. butter
4 c. sifted confectioners' sugar
1 egg yolk
1 (1 oz.) sq. unsweetened chocolate, melted and cooled
1 1/2 tsp. vanilla
1/4 c. light cream

Cream butter; gradually add half the sugar, blending well. Add egg yolk, chocolate, and vanilla. Gradually add remaining sugar; beat well. Add cream to make of spreading consistency. Trim cake with nuts if desired.